A moot question.



63



A MOOT QUESTION.


By Dr. A. G. Butler.


All matters of interest in relation to bird-life should be freely

ventilated, and the experience of many observers brought forward

and tested in order to arrive at the truth. For this reason I have

not hesitated to express my own views touching the change of colour

in certain birds without or with only a partial moult. As a very

strong argument in favour of this view, I quoted the statement (by

not one only, but many winters) regarding the loss of colour in the

wings of the Touracous after they have been exposed to heavy rain,

and its recovery shortly afterwards, in my letter to the Editor,

published in our Magazine for 1918, p. 108.


In his ‘ Ornithologie Nordost Afrikas,’ vol. i, p. 702, Heuglin

says: “ It is known that in consequence of the extremely slight greasi¬

ness of the plumage the latter absorbs much water and thus makes the

bird almost unable to fly. Moreover it has been observed in Touracous

brought alive to Europe that the red colour of the wings gets partly

washed out, which is not the case with prepared dried skins. A

Touracou shot by us during a violent thunderstorm partially lost, when

drying, the beautiful red, which changed into a dirty rusty yellow.”


Then, again, the late Dr. Russ, in his ‘ Fremdliindischen

Stubenvogel,’ vol. ii, p. 668, quotes Herr Meusel as stating : “ All

lose colour when bathing, the water with most of them becoming

reddish, with others greenish”; and on p. 670 he says: “A. E.

Brehm reported in the year 1871, at the February meeting of the

German Ornithological Society, that the feathers of these birds dis¬

colour. If they bathed in clear water a quantity of red colouring-

matter was dissolved in the water.”


Once more Dr. Arthur Stark, in the ‘ Birds of South Africa,’

vol. iii, pp. 215, 216, remarks: “ Perhaps the most interesting

peculiarities about this bird (which it shares with most of the other

members of the family) is the presence of a peculiar red pigment on

the wing-feathers, named by Professor Church (‘Phil. Trans.,’

vol. clix, 1870, pp. 627-636, and vol. clxxxiii a, 1893, p. 511), turacin.


“ This pigment is soluble to a certain extent in water and

exceedingly so in a soapy ( i.e . alkaline) solution, and it has been



